Update event streaming flag docs

Update docs to make it clear that the flag was set to defaulted
on in 14.7.

doc/administration/audit_event_streaming.md

@@ -7,7 +7,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 # Audit event streaming **(ULTIMATE)**
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/332747) in GitLab 14.5 [with a flag](../administration/feature_flags.md) named `ff_external_audit_events_namespace`. Disabled by default.
-> - [Enabled on GitLab.com and self-managed](https://gitlab.com/gitlab-org/gitlab/-/issues/338939) in GitLab 14.7.
+> - [Enabled on GitLab.com and by default on self-managed](https://gitlab.com/gitlab-org/gitlab/-/issues/338939) in GitLab 14.7.
 
 FLAG:
 On self-managed GitLab, by default this feature is available. To hide the feature per group, ask an administrator to [disable the feature flag](../administration/feature_flags.md) named `ff_external_audit_events_namespace`. On GitLab.com, this feature is available.